It is desirable in the case of bibles, reference works, dictionaries, telephone books, timetables, and the like for it to be possible quickly to find a specific heading or a specific subject area by means of a page index, also called a thumb index. Book or page indexes such as this may be in the form either of tabs projecting from fore edges of a page or in the form of notches or recesses in the fore edges of a page by which an indication of the heading or subject area is then to be seen on the page following the page section thereby made visible. Indexes in the form of projecting tabs are generally undesirable, since they, being relatively unprotected, are subjected to heavy stress and are relatively quickly worn off. On the other hand, indexes (thumb indexes) in the form of thumb sections or recesses are relatively well protected, since they extend sideways into the page stack from the fore edge of the pages. Production of these indexes is, of course, relatively labor-intensive, and, because of the manual production usually employed their shape is for the most part irregular and the indexes exhibit a so-called stepped effect.